2. The phenolphthalein indicator changes colour close to the point
of neutralisation which shows the end-point of the titration.
True or false ?

True

Explanation:

A titration can be defined as the experiment where the volume of known con concentration is mixed into another solution whose concentration is not known.

Most of the titration are acid-base titration. When performing titration the indicator which is used is usually phenolphthalein. The end point of the titration is the point where the indicator changes its color.

In case of acid base reaction, the end point is achieved when the phenolpthalein turns faint pink in color from transparent.

Hence, the given statement is correct, the indicator changes its color close to the end point of titration.

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

they are both synthetic elements

explanation:

d